Metal alloy



UNITED STATES PATEN CHRISTIAN IBERGH BACKER, 0F MONTREAL, QUEBEC, CANADA. 1

No Drawing.

To all whom it may concern:

Be it known that I, CHRISTIAN BERGH BAOKER, a subject of the King of Norway, and resident of the city of Montreal, in the Province of Quebec and Dominion of Canada, have invented certain. new and useful Improvements in Metal Alloys, of which the following 'is a full, clear and exact description.

vThis invention relates to a metal alloy, the main object of the invention being to produce a metal having a lower specific gravity than any of the light metal alloys at present in use, yet having equal if not greater strength and toughness.

This new alloy consists of magnesium, aluminum and zinc, the proportion of mag.- nesium being much greater than in any alloy heretofore produced. The proportions of the metals in the alloy may vary approximately from 85% to 98% of magnesium,

- 1% to 141% of aluminum, and .5% to 6% of zinc, the exact composition of the alloy depending upon the use for which it is to be applied. F or' instance, if a hard, closegrained metal is desired, the aluminum content is made comparativ'ely'high and the zinc content comparatively low, but the alloy will then have less ductility and strength.

For producing a hard and coarse-grained metal, both the aluminum and the zinc contents should be high, and approximately the same percentage, say 5%, of each should-be used. For an alloy of great strength and toughness, both the alumlnum and zinc contents should be comparatively low, say not more than 5% aluminum and not more than 3% of zinc. I have also found that for certain purposes, it may be desirable to add small percentages of one or more of the following metals, calcium, copper and cadmium. For example, by adding 1.5% of copper to an alloy of magnesium, aluminum and zinc in approximately the proportions above stated, the strength and toughness of the alloy may be further increased,

but the addition of copper has the disadvantage that the scrap metal can not then be as readily remelted as when. ma nesium, aluminum and zinc only are used. urther, by adding approximately 2% of calcium to the magneslum, -alum1num and zinc, the

hardness of the alloymay be considerably increased withoutreducing its strength and the molten metal is also rendered more flmd g Specification of Letters Patent. Patented June 1, 1920,,

Application filed December so, 1918. Serial mes-8,923. 7

thereby. By adding a small percentage of cadmium, say less than 2%, neither the strength nor hardness of the alloyis afiected,

r creme.

but I have found that the addition of cad- V mium lowers the melting point and makes the alloy more fluid and easier to cast. Whlle the addition of the metals, .calcium,

copper and cadmium in small quantities is found to be useful for the purposes stated,

it is to be understood that they are not essential to the quality ofthe metal produced in an alloy of magnesium, aluminum and zinc in the proportions mentioned.

As the alloy of metals constituting this invention consists of such a large percentage,

over 85%, of magnesium, it is necessary to melt the metals under special conditions to prevent the magnesium from being con-v sumed by combustion. To accomplish this,

the metals in the proportions specified are placed in a crucible from which air is excluded. The molten metal may be then be run. off and cast in special molds. Y The is to cover the magnesium with a flux, then melt the metal, and afterward add the proper proportions of aluminum and zinc until the mass is ready to cast in a mold.

ticularly suitable for use in the manufacture of such parts as pistons and connecting rods for internal combustion engines. It has also been found very suitable for bearings, gears and a great variety of other uses. Castings ofthis alloy may be bent aswell as slightly extended without danger of breaking and by heating the casting to approximately 300 centigrade, it may be hammered and forged into almost any shape. The alloy may also be rolled and drawn under heat. It is not affected to any extent under atmospheric influences and, like aluminum, becomes covered after a short timewith a thin transparent coating ofoxid which prevents further oxidation. This alloy takes a high polish and may be machined very easily and quickly, and in fact, may be preferred method which I employ, however,

turned at speeds several times as high as that used in turningbrass.

Having thus described my invention, What Ic1aimis: g

1. An alloy consisting of not less than 85% and not more than 98% ofmagnesium, not less than 135% and not more than 14% of aluminum and not less than i of 1% nor more than 6% ofvzinc.

- 2. An n10 consisting of magnesium, aluminum an zinc, magnesium constituting more than 85% of the metal, the aluminum more than 1%% and the zinc. more than i of 1% of metal b Weight.

3. A low speci c gravity alloy consisting'15 of magnesium in the proportion of more. than 85%, aluminum more than 1%% and zinc more'than 2 of 1% and adapted to be hardened by the addition of 2% calcium.

In witness whereof I have hereunto set 20 my hand. v

CHRISTIAN BERGH HACKER. 

